Abstract: Aiming at five kinds of typical defects of butt weld of pressure pipeline (incomplete penetration, incomplete fusion, slag inclusion, cracks and pores), the ultrasonic phased array detection simulation was carried out by using CIVA software, and the detection process was determined. At the same time, Israeli ISONIC 2010 phased array device was used to conduct field test on the simulated test tubes containing these five kinds of defects, and the results were compared with the CIVA simulation results to analyze the wave form characteristics of the five kinds of defects. The results show that the CIVA simulation could better guide the development of the detection process, and the extent of agreement with the field test results is as follows: incomplete fusion, incomplete penetration, slag inclusion, pores, cracks, and the phased array testing could replace the ray detection to some extent.